1LESS(1) General Commands Manual LESS(1)
2
6 less - opposite of more
7
9 less -?
10 less --help
11 less -V
12 less --version
13 less [-[+]aABcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~]
14 [-b space] [-h lines] [-j line] [-k keyfile]
15 [-{oO} logfile] [-p pattern] [-P prompt] [-t tag]
16 [-T tagsfile] [-x tab,...] [-y lines] [-[z] lines]
17 [-# shift] [+[+]cmd] [--] [filename]...
18 (See the OPTIONS section for alternate option syntax with long option
19 names.)
20
23 Less is a program similar to more (1), but which allows backward move‐
24 ment in the file as well as forward movement. Also, less does not have
25 to read the entire input file before starting, so with large input
26 files it starts up faster than text editors like vi (1). Less uses
27 termcap (or terminfo on some systems), so it can run on a variety of
28 terminals. There is even limited support for hardcopy terminals. (On
29 a hardcopy terminal, lines which should be printed at the top of the
30 screen are prefixed with a caret.)
31 Commands are based on both more and vi. Commands may be preceded by a
33 decimal number, called N in the descriptions below. The number is used
34 by some commands, as indicated.
35
38 In the following descriptions, ^X means control-X. ESC stands for the
39 ESCAPE key; for example ESC-v means the two character sequence
40 "ESCAPE", then "v".
41 h or H Help: display a summary of these commands. If you forget all
43 the other commands, remember this one.
44 SPACE or ^V or f or ^F
46 Scroll forward N lines, default one window (see option -z
47 below). If N is more than the screen size, only the final
48 screenful is displayed. Warning: some systems use ^V as a spe‐
49 cial literalization character.
50 z Like SPACE, but if N is specified, it becomes the new window
52 size.
53 ESC-SPACE
55 Like SPACE, but scrolls a full screenful, even if it reaches
56 end-of-file in the process.
57 ENTER or RETURN or ^N or e or ^E or j or ^J
59 Scroll forward N lines, default 1. The entire N lines are dis‐
60 played, even if N is more than the screen size.
61 d or ^D
63 Scroll forward N lines, default one half of the screen size. If
64 N is specified, it becomes the new default for subsequent d and
65 u commands.
66 b or ^B or ESC-v
68 Scroll backward N lines, default one window (see option -z
69 below). If N is more than the screen size, only the final
70 screenful is displayed.
71 w Like ESC-v, but if N is specified, it becomes the new window
73 size.
74 y or ^Y or ^P or k or ^K
76 Scroll backward N lines, default 1. The entire N lines are dis‐
77 played, even if N is more than the screen size. Warning: some
78 systems use ^Y as a special job control character.
79 u or ^U
81 Scroll backward N lines, default one half of the screen size.
82 If N is specified, it becomes the new default for subsequent d
83 and u commands.
84 J Like j, but continues to scroll beyond the end of the file.
86 K or Y Like k, but continues to scroll beyond the beginning of the
88 file.
89 ESC-) or RIGHTARROW
91 Scroll horizontally right N characters, default half the screen
92 width (see the -# option). If a number N is specified, it
93 becomes the default for future RIGHTARROW and LEFTARROW com‐
94 mands. While the text is scrolled, it acts as though the -S
95 option (chop lines) were in effect.
96 ESC-( or LEFTARROW
98 Scroll horizontally left N characters, default half the screen
99 width (see the -# option). If a number N is specified, it
100 becomes the default for future RIGHTARROW and LEFTARROW com‐
101 mands.
102 ESC-} or ^RIGHTARROW
104 Scroll horizontally right to show the end of the longest dis‐
105 played line.
106 ESC-{ or ^LEFTARROW
108 Scroll horizontally left back to the first column.
109 r or ^R or ^L
111 Repaint the screen.
112 R Repaint the screen, discarding any buffered input. Useful if
114 the file is changing while it is being viewed.
115 F Scroll forward, and keep trying to read when the end of file is
117 reached. Normally this command would be used when already at
118 the end of the file. It is a way to monitor the tail of a file
119 which is growing while it is being viewed. (The behavior is
120 similar to the "tail -f" command.)
121 ESC-F Like F, but as soon as a line is found which matches the last
123 search pattern, the terminal bell is rung and forward scrolling
124 stops.
125 g or < or ESC-<
127 Go to line N in the file, default 1 (beginning of file). (Warn‐
128 ing: this may be slow if N is large.)
129 G or > or ESC->
131 Go to line N in the file, default the end of the file. (Warn‐
132 ing: this may be slow if N is large, or if N is not specified
133 and standard input, rather than a file, is being read.)
134 ESC-G Same as G, except if no number N is specified and the input is
136 standard input, goes to the last line which is currently
137 buffered.
138 p or % Go to a position N percent into the file. N should be between 0
140 and 100, and may contain a decimal point.
141 P Go to the line containing byte offset N in the file.
143 { If a left curly bracket appears in the top line displayed on the
145 screen, the { command will go to the matching right curly
146 bracket. The matching right curly bracket is positioned on the
147 bottom line of the screen. If there is more than one left curly
148 bracket on the top line, a number N may be used to specify the
149 N-th bracket on the line.
150 } If a right curly bracket appears in the bottom line displayed on
152 the screen, the } command will go to the matching left curly
153 bracket. The matching left curly bracket is positioned on the
154 top line of the screen. If there is more than one right curly
155 bracket on the top line, a number N may be used to specify the
156 N-th bracket on the line.
157 ( Like {, but applies to parentheses rather than curly brackets.
159 ) Like }, but applies to parentheses rather than curly brackets.
161 [ Like {, but applies to square brackets rather than curly brack‐
163 ets.
164 ] Like }, but applies to square brackets rather than curly brack‐
166 ets.
167 ESC-^F Followed by two characters, acts like {, but uses the two char‐
169 acters as open and close brackets, respectively. For example,
170 "ESC ^F < >" could be used to go forward to the > which matches
171 the < in the top displayed line.
172 ESC-^B Followed by two characters, acts like }, but uses the two char‐
174 acters as open and close brackets, respectively. For example,
175 "ESC ^B < >" could be used to go backward to the < which matches
176 the > in the bottom displayed line.
177 m Followed by any lowercase or uppercase letter, marks the first
179 displayed line with that letter. If the status column is
180 enabled via the -J option, the status column shows the marked
181 line.
182 M Acts like m, except the last displayed line is marked rather
184 than the first displayed line.
185 ' (Single quote.) Followed by any lowercase or uppercase letter,
187 returns to the position which was previously marked with that
188 letter. Followed by another single quote, returns to the posi‐
189 tion at which the last "large" movement command was executed.
190 Followed by a ^ or $, jumps to the beginning or end of the file
191 respectively. Marks are preserved when a new file is examined,
192 so the ' command can be used to switch between input files.
193 ^X^X Same as single quote.
195 ESC-m Followed by any lowercase or uppercase letter, clears the mark
197 identified by that letter.
198 /pattern
200 Search forward in the file for the N-th line containing the pat‐
201 tern. N defaults to 1. The pattern is a regular expression, as
202 recognized by the regular expression library supplied by your
203 system. The search starts at the first line displayed (but see
204 the -a and -j options, which change this).
205 Certain characters are special if entered at the beginning of
207 the pattern; they modify the type of search rather than become
208 part of the pattern:
209 ^N or !
211 Search for lines which do NOT match the pattern.
212 ^E or *
214 Search multiple files. That is, if the search reaches
215 the END of the current file without finding a match, the
216 search continues in the next file in the command line
217 list.
218 ^F or @
220 Begin the search at the first line of the FIRST file in
221 the command line list, regardless of what is currently
222 displayed on the screen or the settings of the -a or -j
223 options.
224 ^K Highlight any text which matches the pattern on the cur‐
226 rent screen, but don't move to the first match (KEEP cur‐
227 rent position).
228 ^R Don't interpret regular expression metacharacters; that
230 is, do a simple textual comparison.
231 ?pattern
233 Search backward in the file for the N-th line containing the
234 pattern. The search starts at the last line displayed (but see
235 the -a and -j options, which change this).
236 Certain characters are special as in the / command:
238 ^N or !
240 Search for lines which do NOT match the pattern.
241 ^E or *
243 Search multiple files. That is, if the search reaches
244 the beginning of the current file without finding a
245 match, the search continues in the previous file in the
246 command line list.
247 ^F or @
249 Begin the search at the last line of the last file in the
250 command line list, regardless of what is currently dis‐
251 played on the screen or the settings of the -a or -j
252 options.
253 ^K As in forward searches.
255 ^R As in forward searches.
257 ESC-/pattern
259 Same as "/*".
260 ESC-?pattern
262 Same as "?*".
263 n Repeat previous search, for N-th line containing the last pat‐
265 tern. If the previous search was modified by ^N, the search is
266 made for the N-th line NOT containing the pattern. If the pre‐
267 vious search was modified by ^E, the search continues in the
268 next (or previous) file if not satisfied in the current file.
269 If the previous search was modified by ^R, the search is done
270 without using regular expressions. There is no effect if the
271 previous search was modified by ^F or ^K.
272 N Repeat previous search, but in the reverse direction.
274 ESC-n Repeat previous search, but crossing file boundaries. The
276 effect is as if the previous search were modified by *.
277 ESC-N Repeat previous search, but in the reverse direction and cross‐
279 ing file boundaries.
280 ESC-u Undo search highlighting. Turn off highlighting of strings
282 matching the current search pattern. If highlighting is already
283 off because of a previous ESC-u command, turn highlighting back
284 on. Any search command will also turn highlighting back on.
285 (Highlighting can also be disabled by toggling the -G option; in
286 that case search commands do not turn highlighting back on.)
287 &pattern
289 Display only lines which match the pattern; lines which do not
290 match the pattern are not displayed. If pattern is empty (if
291 you type & immediately followed by ENTER), any filtering is
292 turned off, and all lines are displayed. While filtering is in
293 effect, an ampersand is displayed at the beginning of the
294 prompt, as a reminder that some lines in the file may be hidden.
295 Certain characters are special as in the / command:
297 ^N or !
299 Display only lines which do NOT match the pattern.
300 ^R Don't interpret regular expression metacharacters; that
302 is, do a simple textual comparison.
303 :e [filename]
305 Examine a new file. If the filename is missing, the "current"
306 file (see the :n and :p commands below) from the list of files
307 in the command line is re-examined. A percent sign (%) in the
308 filename is replaced by the name of the current file. A pound
309 sign (#) is replaced by the name of the previously examined
310 file. However, two consecutive percent signs are simply
311 replaced with a single percent sign. This allows you to enter a
312 filename that contains a percent sign in the name. Similarly,
313 two consecutive pound signs are replaced with a single pound
314 sign. The filename is inserted into the command line list of
315 files so that it can be seen by subsequent :n and :p commands.
316 If the filename consists of several files, they are all inserted
317 into the list of files and the first one is examined. If the
318 filename contains one or more spaces, the entire filename should
319 be enclosed in double quotes (also see the -" option).
320 ^X^V or E
322 Same as :e. Warning: some systems use ^V as a special literal‐
323 ization character. On such systems, you may not be able to use
324 ^V.
325 :n Examine the next file (from the list of files given in the com‐
327 mand line). If a number N is specified, the N-th next file is
328 examined.
329 :p Examine the previous file in the command line list. If a number
331 N is specified, the N-th previous file is examined.
332 :x Examine the first file in the command line list. If a number N
334 is specified, the N-th file in the list is examined.
335 :d Remove the current file from the list of files.
337 t Go to the next tag, if there were more than one matches for the
339 current tag. See the -t option for more details about tags.
340 T Go to the previous tag, if there were more than one matches for
342 the current tag.
343 = or ^G or :f
345 Prints some information about the file being viewed, including
346 its name and the line number and byte offset of the bottom line
347 being displayed. If possible, it also prints the length of the
348 file, the number of lines in the file and the percent of the
349 file above the last displayed line.
350 - Followed by one of the command line option letters (see OPTIONS
352 below), this will change the setting of that option and print a
353 message describing the new setting. If a ^P (CONTROL-P) is
354 entered immediately after the dash, the setting of the option is
355 changed but no message is printed. If the option letter has a
356 numeric value (such as -b or -h), or a string value (such as -P
357 or -t), a new value may be entered after the option letter. If
358 no new value is entered, a message describing the current set‐
359 ting is printed and nothing is changed.
360 -- Like the - command, but takes a long option name (see OPTIONS
362 below) rather than a single option letter. You must press ENTER
363 or RETURN after typing the option name. A ^P immediately after
364 the second dash suppresses printing of a message describing the
365 new setting, as in the - command.
366 -+ Followed by one of the command line option letters this will
368 reset the option to its default setting and print a message
369 describing the new setting. (The "-+X" command does the same
370 thing as "-+X" on the command line.) This does not work for
371 string-valued options.
372 --+ Like the -+ command, but takes a long option name rather than a
374 single option letter.
375 -! Followed by one of the command line option letters, this will
377 reset the option to the "opposite" of its default setting and
378 print a message describing the new setting. This does not work
379 for numeric or string-valued options.
380 --! Like the -! command, but takes a long option name rather than a
382 single option letter.
383 _ (Underscore.) Followed by one of the command line option let‐
385 ters, this will print a message describing the current setting
386 of that option. The setting of the option is not changed.
387 __ (Double underscore.) Like the _ (underscore) command, but takes
389 a long option name rather than a single option letter. You must
390 press ENTER or RETURN after typing the option name.
391 +cmd Causes the specified cmd to be executed each time a new file is
393 examined. For example, +G causes less to initially display each
394 file starting at the end rather than the beginning.
395 V Prints the version number of less being run.
397 q or Q or :q or :Q or ZZ
399 Exits less.
400 The following four commands may or may not be valid, depending on your
402 particular installation.
403 v Invokes an editor to edit the current file being viewed. The
405 editor is taken from the environment variable VISUAL if defined,
406 or EDITOR if VISUAL is not defined, or defaults to "vi" if nei‐
407 ther VISUAL nor EDITOR is defined. See also the discussion of
408 LESSEDIT under the section on PROMPTS below.
409 ! shell-command
411 Invokes a shell to run the shell-command given. A percent sign
412 (%) in the command is replaced by the name of the current file.
413 A pound sign (#) is replaced by the name of the previously exam‐
414 ined file. "!!" repeats the last shell command. "!" with no
415 shell command simply invokes a shell. On Unix systems, the
416 shell is taken from the environment variable SHELL, or defaults
417 to "sh". On MS-DOS and OS/2 systems, the shell is the normal
418 command processor.
419 | <m> shell-command
421 <m> represents any mark letter. Pipes a section of the input
422 file to the given shell command. The section of the file to be
423 piped is between the position marked by the letter and the cur‐
424 rent screen. The entire current screen is included, regardless
425 of whether the marked position is before or after the current
426 screen. <m> may also be ^ or $ to indicate beginning or end of
427 file respectively. If <m> is . or newline, the current screen
428 is piped.
429 s filename
431 Save the input to a file. This only works if the input is a
432 pipe, not an ordinary file.
433
435 Command line options are described below. Most options may be changed
436 while less is running, via the "-" command.
437 Most options may be given in one of two forms: either a dash followed
439 by a single letter, or two dashes followed by a long option name. A
440 long option name may be abbreviated as long as the abbreviation is
441 unambiguous. For example, --quit-at-eof may be abbreviated --quit, but
442 not --qui, since both --quit-at-eof and --quiet begin with --qui. Some
443 long option names are in uppercase, such as --QUIT-AT-EOF, as distinct
444 from --quit-at-eof. Such option names need only have their first let‐
445 ter capitalized; the remainder of the name may be in either case. For
446 example, --Quit-at-eof is equivalent to --QUIT-AT-EOF.
447 Options are also taken from the environment variable "LESS". For exam‐
449 ple, to avoid typing "less -options ..." each time less is invoked, you
450 might tell csh:
451 setenv LESS "-options"
453 or if you use sh:
455 LESS="-options"; export LESS
457 On MS-DOS, you don't need the quotes, but you should replace any per‐
459 cent signs in the options string by double percent signs.
460 The environment variable is parsed before the command line, so command
462 line options override the LESS environment variable. If an option
463 appears in the LESS variable, it can be reset to its default value on
464 the command line by beginning the command line option with "-+".
465 Some options like -k or -D require a string to follow the option let‐
467 ter. The string for that option is considered to end when a dollar
468 sign ($) is found. For example, you can set two -D options on MS-DOS
469 like this:
470 LESS="Dn9.1$Ds4.1"
472 If the --use-backslash option appears earlier in the options, then a
474 dollar sign or backslash may be included literally in an option string
475 by preceding it with a backslash. If the --use-backslash option is not
476 in effect, then backslashes are not treated specially, and there is no
477 way to include a dollar sign in the option string.
478 -? or --help
480 This option displays a summary of the commands accepted by less
481 (the same as the h command). (Depending on how your shell
482 interprets the question mark, it may be necessary to quote the
483 question mark, thus: "-\?".)
484 -a or --search-skip-screen
486 By default, forward searches start at the top of the displayed
487 screen and backwards searches start at the bottom of the dis‐
488 played screen (except for repeated searches invoked by the n or
489 N commands, which start after or before the "target" line
490 respectively; see the -j option for more about the target line).
491 The -a option causes forward searches to instead start at the
492 bottom of the screen and backward searches to start at the top
493 of the screen, thus skipping all lines displayed on the screen.
494 -A or --SEARCH-SKIP-SCREEN
496 Causes all forward searches (not just non-repeated searches) to
497 start just after the target line, and all backward searches to
498 start just before the target line. Thus, forward searches will
499 skip part of the displayed screen (from the first line up to and
500 including the target line). Similarly backwards searches will
501 skip the displayed screen from the last line up to and including
502 the target line. This was the default behavior in less versions
503 prior to 441.
504 -bn or --buffers=n
506 Specifies the amount of buffer space less will use for each
507 file, in units of kilobytes (1024 bytes). By default 64 K of
508 buffer space is used for each file (unless the file is a pipe;
509 see the -B option). The -b option specifies instead that n
510 kilobytes of buffer space should be used for each file. If n is
511 -1, buffer space is unlimited; that is, the entire file can be
512 read into memory.
513 -B or --auto-buffers
515 By default, when data is read from a pipe, buffers are allocated
516 automatically as needed. If a large amount of data is read from
517 the pipe, this can cause a large amount of memory to be allo‐
518 cated. The -B option disables this automatic allocation of buf‐
519 fers for pipes, so that only 64 K (or the amount of space speci‐
520 fied by the -b option) is used for the pipe. Warning: use of -B
521 can result in erroneous display, since only the most recently
522 viewed part of the piped data is kept in memory; any earlier
523 data is lost.
524 -c or --clear-screen
526 Causes full screen repaints to be painted from the top line
527 down. By default, full screen repaints are done by scrolling
528 from the bottom of the screen.
529 -C or --CLEAR-SCREEN
531 Same as -c, for compatibility with older versions of less.
532 -d or --dumb
534 The -d option suppresses the error message normally displayed if
535 the terminal is dumb; that is, lacks some important capability,
536 such as the ability to clear the screen or scroll backward. The
537 -d option does not otherwise change the behavior of less on a
538 dumb terminal.
539 -Dxcolor or --color=xcolor
541 [MS-DOS only] Sets the color of the text displayed. x is a sin‐
542 gle character which selects the type of text whose color is
543 being set: n=normal, s=standout, d=bold, u=underlined, k=blink.
544 color is a pair of numbers separated by a period. The first
545 number selects the foreground color and the second selects the
546 background color of the text. A single number N is the same as
547 N.M, where M is the normal background color. The color may
548 start or end with u to use underline (with the normal color, if
549 by itself), if the system supports it (Windows only). x may
550 also be a to toggle strict ANSI sequence rendering (SGR mode).
551 -e or --quit-at-eof
554 Causes less to automatically exit the second time it reaches
555 end-of-file. By default, the only way to exit less is via the
556 "q" command.
557 -E or --QUIT-AT-EOF
559 Causes less to automatically exit the first time it reaches end-
560 of-file.
561 -f or --force
563 Forces non-regular files to be opened. (A non-regular file is a
564 directory or a device special file.) Also suppresses the warn‐
565 ing message when a binary file is opened. By default, less will
566 refuse to open non-regular files. Note that some operating sys‐
567 tems will not allow directories to be read, even if -f is set.
568 -F or --quit-if-one-screen
570 Causes less to automatically exit if the entire file can be dis‐
571 played on the first screen.
572 -g or --hilite-search
574 Normally, less will highlight ALL strings which match the last
575 search command. The -g option changes this behavior to high‐
576 light only the particular string which was found by the last
577 search command. This can cause less to run somewhat faster than
578 the default.
579 -G or --HILITE-SEARCH
581 The -G option suppresses all highlighting of strings found by
582 search commands.
583 --old-bot
585 Reverts to the old bottom of screen behavior. This can be some‐
586 times desirable if the long lines are not wrapped correctly
587 when reaching the bottom of the terminal, while scrolling
588 forward.
589 -hn or --max-back-scroll=n
591 Specifies a maximum number of lines to scroll backward. If it
592 is necessary to scroll backward more than n lines, the screen is
593 repainted in a forward direction instead. (If the terminal does
594 not have the ability to scroll backward, -h0 is implied.)
595 -i or --ignore-case
597 Causes searches to ignore case; that is, uppercase and lowercase
598 are considered identical. This option is ignored if any upper‐
599 case letters appear in the search pattern; in other words, if a
600 pattern contains uppercase letters, then that search does not
601 ignore case.
602 -I or --IGNORE-CASE
604 Like -i, but searches ignore case even if the pattern contains
605 uppercase letters.
606 -jn or --jump-target=n
608 Specifies a line on the screen where the "target" line is to be
609 positioned. The target line is the line specified by any com‐
610 mand to search for a pattern, jump to a line number, jump to a
611 file percentage or jump to a tag. The screen line may be speci‐
612 fied by a number: the top line on the screen is 1, the next is
613 2, and so on. The number may be negative to specify a line rel‐
614 ative to the bottom of the screen: the bottom line on the screen
615 is -1, the second to the bottom is -2, and so on. Alternately,
616 the screen line may be specified as a fraction of the height of
617 the screen, starting with a decimal point: .5 is in the middle
618 of the screen, .3 is three tenths down from the first line, and
619 so on. If the line is specified as a fraction, the actual line
620 number is recalculated if the terminal window is resized, so
621 that the target line remains at the specified fraction of the
622 screen height. If any form of the -j option is used, repeated
623 forward searches (invoked with "n" or "N") begin at the line
624 immediately after the target line, and repeated backward
625 searches begin at the target line, unless changed by -a or -A.
626 For example, if "-j4" is used, the target line is the fourth
627 line on the screen, so forward searches begin at the fifth line
628 on the screen. However nonrepeated searches (invoked with "/"
629 or "?") always begin at the start or end of the current screen
630 respectively.
631 -J or --status-column
633 Displays a status column at the left edge of the screen. The
634 status column shows the lines that matched the current search,
635 and any lines that are marked (via the m or M command). The
636 status column is also used if the -w or -W option is in effect.
637 -kfilename or --lesskey-file=filename
639 Causes less to open and interpret the named file as a lesskey
640 (1) file. Multiple -k options may be specified. If the LESSKEY
641 or LESSKEY_SYSTEM environment variable is set, or if a lesskey
642 file is found in a standard place (see KEY BINDINGS), it is also
643 used as a lesskey file.
644 -K or --quit-on-intr
646 Causes less to exit immediately (with status 2) when an inter‐
647 rupt character (usually ^C) is typed. Normally, an interrupt
648 character causes less to stop whatever it is doing and return to
649 its command prompt. Note that use of this option makes it
650 impossible to return to the command prompt from the "F" command.
651 -L or --no-lessopen
653 Ignore the LESSOPEN environment variable (see the INPUT PRE‐
654 PROCESSOR section below). This option can be set from within
655 less, but it will apply only to files opened subsequently, not
656 to the file which is currently open.
657 -m or --long-prompt
659 Causes less to prompt verbosely (like more), with the percent
660 into the file. By default, less prompts with a colon.
661 -M or --LONG-PROMPT
663 Causes less to prompt even more verbosely than more.
664 -n or --line-numbers
666 Suppresses line numbers. The default (to use line numbers) may
667 cause less to run more slowly in some cases, especially with a
668 very large input file. Suppressing line numbers with the -n
669 option will avoid this problem. Using line numbers means: the
670 line number will be displayed in the verbose prompt and in the =
671 command, and the v command will pass the current line number to
672 the editor (see also the discussion of LESSEDIT in PROMPTS
673 below).
674 -N or --LINE-NUMBERS
676 Causes a line number to be displayed at the beginning of each
677 line in the display.
678 -ofilename or --log-file=filename
680 Causes less to copy its input to the named file as it is being
681 viewed. This applies only when the input file is a pipe, not an
682 ordinary file. If the file already exists, less will ask for
683 confirmation before overwriting it.
684 -Ofilename or --LOG-FILE=filename
686 The -O option is like -o, but it will overwrite an existing file
687 without asking for confirmation.
688 If no log file has been specified, the -o and -O options can be
690 used from within less to specify a log file. Without a file
691 name, they will simply report the name of the log file. The "s"
692 command is equivalent to specifying -o from within less.
693 -ppattern or --pattern=pattern
695 The -p option on the command line is equivalent to specifying
696 +/pattern; that is, it tells less to start at the first occur‐
697 rence of pattern in the file.
698 -Pprompt or --prompt=prompt
700 Provides a way to tailor the three prompt styles to your own
701 preference. This option would normally be put in the LESS envi‐
702 ronment variable, rather than being typed in with each less com‐
703 mand. Such an option must either be the last option in the LESS
704 variable, or be terminated by a dollar sign.
705 -Ps followed by a string changes the default (short) prompt to
706 that string.
707 -Pm changes the medium (-m) prompt.
708 -PM changes the long (-M) prompt.
709 -Ph changes the prompt for the help screen.
710 -P= changes the message printed by the = command.
711 -Pw changes the message printed while waiting for data (in the
712 F command).
713 All prompt strings consist of a sequence of letters and special
715 escape sequences. See the section on PROMPTS for more details.
716 -q or --quiet or --silent
718 Causes moderately "quiet" operation: the terminal bell is not
719 rung if an attempt is made to scroll past the end of the file or
720 before the beginning of the file. If the terminal has a "visual
721 bell", it is used instead. The bell will be rung on certain
722 other errors, such as typing an invalid character. The default
723 is to ring the terminal bell in all such cases.
724 -Q or --QUIET or --SILENT
726 Causes totally "quiet" operation: the terminal bell is never
727 rung. If the terminal has a "visual bell", it is used in all
728 cases where the terminal bell would have been rung.
729 -r or --raw-control-chars
731 Causes "raw" control characters to be displayed. The default is
732 to display control characters using the caret notation; for
733 example, a control-A (octal 001) is displayed as "^A". Warning:
734 when the -r option is used, less cannot keep track of the actual
735 appearance of the screen (since this depends on how the screen
736 responds to each type of control character). Thus, various dis‐
737 play problems may result, such as long lines being split in the
738 wrong place.
739 -R or --RAW-CONTROL-CHARS
741 Like -r, but only ANSI "color" escape sequences are output in
742 "raw" form. Unlike -r, the screen appearance is maintained cor‐
743 rectly in most cases. ANSI "color" escape sequences are
744 sequences of the form:
745 ESC [ ... m
747 where the "..." is zero or more color specification characters
749 For the purpose of keeping track of screen appearance, ANSI
750 color escape sequences are assumed to not move the cursor. You
751 can make less think that characters other than "m" can end ANSI
752 color escape sequences by setting the environment variable
753 LESSANSIENDCHARS to the list of characters which can end a color
754 escape sequence. And you can make less think that characters
755 other than the standard ones may appear between the ESC and the
756 m by setting the environment variable LESSANSIMIDCHARS to the
757 list of characters which can appear.
758 -s or --squeeze-blank-lines
760 Causes consecutive blank lines to be squeezed into a single
761 blank line. This is useful when viewing nroff output.
762 -S or --chop-long-lines
764 Causes lines longer than the screen width to be chopped (trun‐
765 cated) rather than wrapped. That is, the portion of a long line
766 that does not fit in the screen width is not shown. The default
767 is to wrap long lines; that is, display the remainder on the
768 next line.
769 -ttag or --tag=tag
771 The -t option, followed immediately by a TAG, will edit the file
772 containing that tag. For this to work, tag information must be
773 available; for example, there may be a file in the current
774 directory called "tags", which was previously built by ctags (1)
775 or an equivalent command. If the environment variable LESSGLOB‐
776 ALTAGS is set, it is taken to be the name of a command compati‐
777 ble with global (1), and that command is executed to find the
778 tag. (See http://www.gnu.org/software/global/global.html). The
779 -t option may also be specified from within less (using the -
780 command) as a way of examining a new file. The command ":t" is
781 equivalent to specifying -t from within less.
782 -Ttagsfile or --tag-file=tagsfile
784 Specifies a tags file to be used instead of "tags".
785 -u or --underline-special
787 Causes backspaces and carriage returns to be treated as print‐
788 able characters; that is, they are sent to the terminal when
789 they appear in the input.
790 -U or --UNDERLINE-SPECIAL
792 Causes backspaces, tabs, carriage returns and "formatting char‐
793 acters" (as defined by Unicode) to be treated as control charac‐
794 ters; that is, they are handled as specified by the -r option.
795 By default, if neither -u nor -U is given, backspaces which
797 appear adjacent to an underscore character are treated spe‐
798 cially: the underlined text is displayed using the terminal's
799 hardware underlining capability. Also, backspaces which appear
800 between two identical characters are treated specially: the
801 overstruck text is printed using the terminal's hardware bold‐
802 face capability. Other backspaces are deleted, along with the
803 preceding character. Carriage returns immediately followed by a
804 newline are deleted. Other carriage returns are handled as
805 specified by the -r option. Text which is overstruck or under‐
806 lined can be searched for if neither -u nor -U is in effect.
807 -V or --version
809 Displays the version number of less.
810 -w or --hilite-unread
812 Temporarily highlights the first "new" line after a forward
813 movement of a full page. The first "new" line is the line imme‐
814 diately following the line previously at the bottom of the
815 screen. Also highlights the target line after a g or p command.
816 The highlight is removed at the next command which causes move‐
817 ment. The entire line is highlighted, unless the -J option is
818 in effect, in which case only the status column is highlighted.
819 -W or --HILITE-UNREAD
821 Like -w, but temporarily highlights the first new line after any
822 forward movement command larger than one line.
823 -xn,... or --tabs=n,...
825 Sets tab stops. If only one n is specified, tab stops are set
826 at multiples of n. If multiple values separated by commas are
827 specified, tab stops are set at those positions, and then con‐
828 tinue with the same spacing as the last two. For example,
829 -x9,17 will set tabs at positions 9, 17, 25, 33, etc. The
830 default for n is 8.
831 -X or --no-init
833 Disables sending the termcap initialization and deinitialization
834 strings to the terminal. This is sometimes desirable if the
835 deinitialization string does something unnecessary, like clear‐
836 ing the screen.
837 -yn or --max-forw-scroll=n
839 Specifies a maximum number of lines to scroll forward. If it is
840 necessary to scroll forward more than n lines, the screen is
841 repainted instead. The -c or -C option may be used to repaint
842 from the top of the screen if desired. By default, any forward
843 movement causes scrolling.
844 -zn or --window=n or -n
846 Changes the default scrolling window size to n lines. The
847 default is one screenful. The z and w commands can also be used
848 to change the window size. The "z" may be omitted for compati‐
849 bility with some versions of more. If the number n is negative,
850 it indicates n lines less than the current screen size. For
851 example, if the screen is 24 lines, -z-4 sets the scrolling win‐
852 dow to 20 lines. If the screen is resized to 40 lines, the
853 scrolling window automatically changes to 36 lines.
854 -"cc or --quotes=cc
856 Changes the filename quoting character. This may be necessary
857 if you are trying to name a file which contains both spaces and
858 quote characters. Followed by a single character, this changes
859 the quote character to that character. Filenames containing a
860 space should then be surrounded by that character rather than by
861 double quotes. Followed by two characters, changes the open
862 quote to the first character, and the close quote to the second
863 character. Filenames containing a space should then be preceded
864 by the open quote character and followed by the close quote
865 character. Note that even after the quote characters are
866 changed, this option remains -" (a dash followed by a double
867 quote).
868 -~ or --tilde
870 Normally lines after end of file are displayed as a single tilde
871 (~). This option causes lines after end of file to be displayed
872 as blank lines.
873 -# or --shift
875 Specifies the default number of positions to scroll horizontally
876 in the RIGHTARROW and LEFTARROW commands. If the number speci‐
877 fied is zero, it sets the default number of positions to one
878 half of the screen width. Alternately, the number may be speci‐
879 fied as a fraction of the width of the screen, starting with a
880 decimal point: .5 is half of the screen width, .3 is three
881 tenths of the screen width, and so on. If the number is speci‐
882 fied as a fraction, the actual number of scroll positions is
883 recalculated if the terminal window is resized, so that the
884 actual scroll remains at the specified fraction of the screen
885 width.
886 --follow-name
888 Normally, if the input file is renamed while an F command is
889 executing, less will continue to display the contents of the
890 original file despite its name change. If --follow-name is
891 specified, during an F command less will periodically attempt to
892 reopen the file by name. If the reopen succeeds and the file is
893 a different file from the original (which means that a new file
894 has been created with the same name as the original (now
895 renamed) file), less will display the contents of that new file.
896 --mouse
898 Enables mouse input: scrolling the mouse wheel down moves for‐
899 ward in the file, scrolling the mouse wheel up moves backwards
900 in the file, and clicking the mouse sets the "#" mark to the
901 line where the mouse is clicked. The number of lines to scroll
902 when the wheel is moved can be set by the --wheel-lines option.
903 Mouse input works only on terminals which support X11 mouse
904 reporting, and on the Windows version of less.
905 --MOUSE
907 Like --mouse, except the direction scrolled on mouse wheel move‐
908 ment is reversed.
909 --no-keypad
911 Disables sending the keypad initialization and deinitialization
912 strings to the terminal. This is sometimes useful if the keypad
913 strings make the numeric keypad behave in an undesirable manner.
914 --no-histdups
916 This option changes the behavior so that if a search string or
917 file name is typed in, and the same string is already in the
918 history list, the existing copy is removed from the history list
919 before the new one is added. Thus, a given string will appear
920 only once in the history list. Normally, a string may appear
921 multiple times.
922 --rscroll
924 This option changes the character used to mark truncated lines.
925 It may begin with a two-character attribute indicator like LESS‐
926 BINFMT does. If there is no attribute indicator, standout is
927 used. If set to "-", truncated lines are not marked.
928 --save-marks
930 Save marks in the history file, so marks are retained across
931 different invocations of less.
932 --use-backslash
934 This option changes the interpretations of options which follow
935 this one. After the --use-backslash option, any backslash in an
936 option string is removed and the following character is taken
937 literally. This allows a dollar sign to be included in option
938 strings.
939 --wheel-lines=n
941 Set the number of lines to scroll when the mouse wheel is
942 scrolled and the --mouse or --MOUSE option is in effect. The
943 default is 1 line.
944 -- A command line argument of "--" marks the end of option argu‐
946 ments. Any arguments following this are interpreted as file‐
947 names. This can be useful when viewing a file whose name begins
948 with a "-" or "+".
949 + If a command line option begins with +, the remainder of that
951 option is taken to be an initial command to less. For example,
952 +G tells less to start at the end of the file rather than the
953 beginning, and +/xyz tells it to start at the first occurrence
954 of "xyz" in the file. As a special case, +<number> acts like
955 +<number>g; that is, it starts the display at the specified line
956 number (however, see the caveat under the "g" command above).
957 If the option starts with ++, the initial command applies to
958 every file being viewed, not just the first one. The + command
959 described previously may also be used to set (or change) an ini‐
960 tial command for every file.
961
964 When entering command line at the bottom of the screen (for example, a
965 filename for the :e command, or the pattern for a search command), cer‐
966 tain keys can be used to manipulate the command line. Most commands
967 have an alternate form in [ brackets ] which can be used if a key does
968 not exist on a particular keyboard. (Note that the forms beginning
969 with ESC do not work in some MS-DOS and Windows systems because ESC is
970 the line erase character.) Any of these special keys may be entered
971 literally by preceding it with the "literal" character, either ^V or
972 ^A. A backslash itself may also be entered literally by entering two
973 backslashes.
974 LEFTARROW [ ESC-h ]
976 Move the cursor one space to the left.
977 RIGHTARROW [ ESC-l ]
979 Move the cursor one space to the right.
980 ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
982 (That is, CONTROL and LEFTARROW simultaneously.) Move the cur‐
983 sor one word to the left.
984 ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
986 (That is, CONTROL and RIGHTARROW simultaneously.) Move the cur‐
987 sor one word to the right.
988 HOME [ ESC-0 ]
990 Move the cursor to the beginning of the line.
991 END [ ESC-$ ]
993 Move the cursor to the end of the line.
994 BACKSPACE
996 Delete the character to the left of the cursor, or cancel the
997 command if the command line is empty.
998 DELETE or [ ESC-x ]
1000 Delete the character under the cursor.
1001 ^BACKSPACE [ ESC-BACKSPACE ]
1003 (That is, CONTROL and BACKSPACE simultaneously.) Delete the
1004 word to the left of the cursor.
1005 ^DELETE [ ESC-X or ESC-DELETE ]
1007 (That is, CONTROL and DELETE simultaneously.) Delete the word
1008 under the cursor.
1009 UPARROW [ ESC-k ]
1011 Retrieve the previous command line. If you first enter some
1012 text and then press UPARROW, it will retrieve the previous com‐
1013 mand which begins with that text.
1014 DOWNARROW [ ESC-j ]
1016 Retrieve the next command line. If you first enter some text
1017 and then press DOWNARROW, it will retrieve the next command
1018 which begins with that text.
1019 TAB Complete the partial filename to the left of the cursor. If it
1021 matches more than one filename, the first match is entered into
1022 the command line. Repeated TABs will cycle thru the other
1023 matching filenames. If the completed filename is a directory, a
1024 "/" is appended to the filename. (On MS-DOS systems, a "\" is
1025 appended.) The environment variable LESSSEPARATOR can be used
1026 to specify a different character to append to a directory name.
1027 BACKTAB [ ESC-TAB ]
1029 Like, TAB, but cycles in the reverse direction thru the matching
1030 filenames.
1031 ^L Complete the partial filename to the left of the cursor. If it
1033 matches more than one filename, all matches are entered into the
1034 command line (if they fit).
1035 ^U (Unix and OS/2) or ESC (MS-DOS)
1037 Delete the entire command line, or cancel the command if the
1038 command line is empty. If you have changed your line-kill char‐
1039 acter in Unix to something other than ^U, that character is used
1040 instead of ^U.
1041 ^G Delete the entire command line and return to the main prompt.
1043
1046 You may define your own less commands by using the program lesskey (1)
1047 to create a lesskey file. This file specifies a set of command keys
1048 and an action associated with each key. You may also use lesskey to
1049 change the line-editing keys (see LINE EDITING), and to set environment
1050 variables. If the environment variable LESSKEY is set, less uses that
1051 as the name of the lesskey file. Otherwise, less looks in a standard
1052 place for the lesskey file: On Unix systems, less looks for a lesskey
1053 file called "$HOME/.less". On MS-DOS and Windows systems, less looks
1054 for a lesskey file called "$HOME/_less", and if it is not found there,
1055 then looks for a lesskey file called "_less" in any directory specified
1056 in the PATH environment variable. On OS/2 systems, less looks for a
1057 lesskey file called "$HOME/less.ini", and if it is not found, then
1058 looks for a lesskey file called "less.ini" in any directory specified
1059 in the INIT environment variable, and if it not found there, then looks
1060 for a lesskey file called "less.ini" in any directory specified in the
1061 PATH environment variable. See the lesskey manual page for more
1062 details.
1063 A system-wide lesskey file may also be set up to provide key bindings.
1065 If a key is defined in both a local lesskey file and in the system-wide
1066 file, key bindings in the local file take precedence over those in the
1067 system-wide file. If the environment variable LESSKEY_SYSTEM is set,
1068 less uses that as the name of the system-wide lesskey file. Otherwise,
1069 less looks in a standard place for the system-wide lesskey file: On
1070 Unix systems, the system-wide lesskey file is /usr/local/etc/sysless.
1071 (However, if less was built with a different sysconf directory than
1072 /usr/local/etc, that directory is where the sysless file is found.) On
1073 MS-DOS and Windows systems, the system-wide lesskey file is c:\_sys‐
1074 less. On OS/2 systems, the system-wide lesskey file is c:\sysless.ini.
1075
1078 You may define an "input preprocessor" for less. Before less opens a
1079 file, it first gives your input preprocessor a chance to modify the way
1080 the contents of the file are displayed. An input preprocessor is sim‐
1081 ply an executable program (or shell script), which writes the contents
1082 of the file to a different file, called the replacement file. The con‐
1083 tents of the replacement file are then displayed in place of the con‐
1084 tents of the original file. However, it will appear to the user as if
1085 the original file is opened; that is, less will display the original
1086 filename as the name of the current file.
1087 An input preprocessor receives one command line argument, the original
1089 filename, as entered by the user. It should create the replacement
1090 file, and when finished, print the name of the replacement file to its
1091 standard output. If the input preprocessor does not output a replace‐
1092 ment filename, less uses the original file, as normal. The input pre‐
1093 processor is not called when viewing standard input. To set up an
1094 input preprocessor, set the LESSOPEN environment variable to a command
1095 line which will invoke your input preprocessor. This command line
1096 should include one occurrence of the string "%s", which will be
1097 replaced by the filename when the input preprocessor command is
1098 invoked.
1099 When less closes a file opened in such a way, it will call another pro‐
1101 gram, called the input postprocessor, which may perform any desired
1102 clean-up action (such as deleting the replacement file created by
1103 LESSOPEN). This program receives two command line arguments, the orig‐
1104 inal filename as entered by the user, and the name of the replacement
1105 file. To set up an input postprocessor, set the LESSCLOSE environment
1106 variable to a command line which will invoke your input postprocessor.
1107 It may include two occurrences of the string "%s"; the first is
1108 replaced with the original name of the file and the second with the
1109 name of the replacement file, which was output by LESSOPEN.
1110 For example, on many Unix systems, these two scripts will allow you to
1112 keep files in compressed format, but still let less view them directly:
1113 lessopen.sh:
1115 #! /bin/sh
1116 case "$1" in
1117 *.Z) TEMPFILE=$(mktemp)
1118 uncompress -c $1 >$TEMPFILE 2>/dev/null
1119 if [ -s $TEMPFILE ]; then
1120 echo $TEMPFILE
1121 else
1122 rm -f $TEMPFILE
1123 fi
1124 ;;
1125 esac
1126 lessclose.sh:
1128 #! /bin/sh
1129 rm $2
1130 To use these scripts, put them both where they can be executed and set
1132 LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More
1133 complex LESSOPEN and LESSCLOSE scripts may be written to accept other
1134 types of compressed files, and so on.
1135 It is also possible to set up an input preprocessor to pipe the file
1137 data directly to less, rather than putting the data into a replacement
1138 file. This avoids the need to decompress the entire file before start‐
1139 ing to view it. An input preprocessor that works this way is called an
1140 input pipe. An input pipe, instead of writing the name of a replace‐
1141 ment file on its standard output, writes the entire contents of the
1142 replacement file on its standard output. If the input pipe does not
1143 write any characters on its standard output, then there is no replace‐
1144 ment file and less uses the original file, as normal. To use an input
1145 pipe, make the first character in the LESSOPEN environment variable a
1146 vertical bar (|) to signify that the input preprocessor is an input
1147 pipe. As with non-pipe input preprocessors, the command string must
1148 contain one occurrence of %s, which is replaced with the filename of
1149 the input file.
1150 For example, on many Unix systems, this script will work like the pre‐
1152 vious example scripts:
1153 lesspipe.sh:
1155 #! /bin/sh
1156 case "$1" in
1157 *.Z) uncompress -c $1 2>/dev/null
1158 ;;
1159 *) exit 1
1160 ;;
1161 esac
1162 exit $?
1163 To use this script, put it where it can be executed and set
1165 LESSOPEN="|lesspipe.sh %s".
1166 Note that a preprocessor cannot output an empty file, since that is
1168 interpreted as meaning there is no replacement, and the original file
1169 is used. To avoid this, if LESSOPEN starts with two vertical bars, the
1170 exit status of the script becomes meaningful. If the exit status is
1171 zero, the output is considered to be replacement text, even if it is
1172 empty. If the exit status is nonzero, any output is ignored and the
1173 original file is used. For compatibility with previous versions of
1174 less, if LESSOPEN starts with only one vertical bar, the exit status of
1175 the preprocessor is ignored.
1176 When an input pipe is used, a LESSCLOSE postprocessor can be used, but
1178 it is usually not necessary since there is no replacement file to clean
1179 up. In this case, the replacement file name passed to the LESSCLOSE
1180 postprocessor is "-".
1181 For compatibility with previous versions of less, the input preproces‐
1183 sor or pipe is not used if less is viewing standard input. However, if
1184 the first character of LESSOPEN is a dash (-), the input preprocessor
1185 is used on standard input as well as other files. In this case, the
1186 dash is not considered to be part of the preprocessor command. If
1187 standard input is being viewed, the input preprocessor is passed a file
1188 name consisting of a single dash. Similarly, if the first two charac‐
1189 ters of LESSOPEN are vertical bar and dash (|-) or two vertical bars
1190 and a dash (||-), the input pipe is used on standard input as well as
1191 other files. Again, in this case the dash is not considered to be part
1192 of the input pipe command.
1193 There are used following files to set up default preprocessor:
1195 /etc/profile.d/less.sh
1196 /etc/profile.d/less.csh
1197 These files set up /usr/bin/lesspipe.sh as a default filter. An user
1198 defined filter can be specified in ~/.lessfilter. This file should have
1199 an execute bit set and accept only one parameter, which represents a
1200 filename. If the user defined filter process the file, zero should be
1201 returned. Otherwise ~/.lessfilter tries to handle the file.
1202
1205 There are three types of characters in the input file:
1206 normal characters
1208 can be displayed directly to the screen.
1209 control characters
1211 should not be displayed directly, but are expected to be found
1212 in ordinary text files (such as backspace and tab).
1213 binary characters
1215 should not be displayed directly and are not expected to be
1216 found in text files.
1217 A "character set" is simply a description of which characters are to be
1219 considered normal, control, and binary. The LESSCHARSET environment
1220 variable may be used to select a character set. Possible values for
1221 LESSCHARSET are:
1222 ascii BS, TAB, NL, CR, and formfeed are control characters, all chars
1224 with values between 32 and 126 are normal, and all others are
1225 binary.
1226 iso8859
1228 Selects an ISO 8859 character set. This is the same as ASCII,
1229 except characters between 160 and 255 are treated as normal
1230 characters.
1231 latin1 Same as iso8859.
1233 latin9 Same as iso8859.
1235 dos Selects a character set appropriate for MS-DOS.
1237 ebcdic Selects an EBCDIC character set.
1239 IBM-1047
1241 Selects an EBCDIC character set used by OS/390 Unix Services.
1242 This is the EBCDIC analogue of latin1. You get similar results
1243 by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your
1244 environment.
1245 koi8-r Selects a Russian character set.
1247 next Selects a character set appropriate for NeXT computers.
1249 utf-8 Selects the UTF-8 encoding of the ISO 10646 character set.
1251 UTF-8 is special in that it supports multi-byte characters in
1252 the input file. It is the only character set that supports
1253 multi-byte characters.
1254 windows
1256 Selects a character set appropriate for Microsoft Windows (cp
1257 1251).
1258 In rare cases, it may be desired to tailor less to use a character set
1260 other than the ones definable by LESSCHARSET. In this case, the envi‐
1261 ronment variable LESSCHARDEF can be used to define a character set. It
1262 should be set to a string where each character in the string represents
1263 one character in the character set. The character "." is used for a
1264 normal character, "c" for control, and "b" for binary. A decimal num‐
1265 ber may be used for repetition. For example, "bccc4b." would mean
1266 character 0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7 are
1267 binary, and 8 is normal. All characters after the last are taken to be
1268 the same as the last, so characters 9 through 255 would be normal.
1269 (This is an example, and does not necessarily represent any real char‐
1270 acter set.)
1271 This table shows the value of LESSCHARDEF which is equivalent to each
1273 of the possible values for LESSCHARSET:
1274 ascii 8bcccbcc18b95.b
1276 dos 8bcccbcc12bc5b95.b.
1277 ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b
1278 9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b.
1279 IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc
1280 191.b
1281 iso8859 8bcccbcc18b95.33b.
1282 koi8-r 8bcccbcc18b95.b128.
1283 latin1 8bcccbcc18b95.33b.
1284 next 8bcccbcc18b95.bb125.bb
1285 If neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings
1287 "UTF-8", "UTF8", "utf-8" or "utf8" is found in the LC_ALL, LC_CTYPE or
1288 LANG environment variables, then the default character set is utf-8.
1289 If that string is not found, but your system supports the setlocale
1291 interface, less will use setlocale to determine the character set.
1292 setlocale is controlled by setting the LANG or LC_CTYPE environment
1293 variables.
1294 Finally, if the setlocale interface is also not available, the default
1296 character set is latin1.
1297 Control and binary characters are displayed in standout (reverse
1299 video). Each such character is displayed in caret notation if possible
1300 (e.g. ^A for control-A). Caret notation is used only if inverting the
1301 0100 bit results in a normal printable character. Otherwise, the char‐
1302 acter is displayed as a hex number in angle brackets. This format can
1303 be changed by setting the LESSBINFMT environment variable. LESSBINFMT
1304 may begin with a "*" and one character to select the display attribute:
1305 "*k" is blinking, "*d" is bold, "*u" is underlined, "*s" is standout,
1306 and "*n" is normal. If LESSBINFMT does not begin with a "*", normal
1307 attribute is assumed. The remainder of LESSBINFMT is a string which
1308 may include one printf-style escape sequence (a % followed by x, X, o,
1309 d, etc.). For example, if LESSBINFMT is "*u[%x]", binary characters
1310 are displayed in underlined hexadecimal surrounded by brackets. The
1311 default if no LESSBINFMT is specified is "*s<%02X>". Warning: the
1312 result of expanding the character via LESSBINFMT must be less than 31
1313 characters.
1314 When the character set is utf-8, the LESSUTFBINFMT environment variable
1316 acts similarly to LESSBINFMT but it applies to Unicode code points that
1317 were successfully decoded but are unsuitable for display (e.g., unas‐
1318 signed code points). Its default value is "<U+%04lX>". Note that
1319 LESSUTFBINFMT and LESSBINFMT share their display attribute setting
1320 ("*x") so specifying one will affect both; LESSUTFBINFMT is read after
1321 LESSBINFMT so its setting, if any, will have priority. Problematic
1322 octets in a UTF-8 file (octets of a truncated sequence, octets of a
1323 complete but non-shortest form sequence, illegal octets, and stray
1324 trailing octets) are displayed individually using LESSBINFMT so as to
1325 facilitate diagnostic of how the UTF-8 file is ill-formed.
1326
1329 The -P option allows you to tailor the prompt to your preference. The
1330 string given to the -P option replaces the specified prompt string.
1331 Certain characters in the string are interpreted specially. The prompt
1332 mechanism is rather complicated to provide flexibility, but the ordi‐
1333 nary user need not understand the details of constructing personalized
1334 prompt strings.
1335 A percent sign followed by a single character is expanded according to
1337 what the following character is:
1338 %bX Replaced by the byte offset into the current input file. The b
1340 is followed by a single character (shown as X above) which spec‐
1341 ifies the line whose byte offset is to be used. If the charac‐
1342 ter is a "t", the byte offset of the top line in the display is
1343 used, an "m" means use the middle line, a "b" means use the bot‐
1344 tom line, a "B" means use the line just after the bottom line,
1345 and a "j" means use the "target" line, as specified by the -j
1346 option.
1347 %B Replaced by the size of the current input file.
1349 %c Replaced by the column number of the text appearing in the first
1351 column of the screen.
1352 %dX Replaced by the page number of a line in the input file. The
1354 line to be used is determined by the X, as with the %b option.
1355 %D Replaced by the number of pages in the input file, or equiva‐
1357 lently, the page number of the last line in the input file.
1358 %E Replaced by the name of the editor (from the VISUAL environment
1360 variable, or the EDITOR environment variable if VISUAL is not
1361 defined). See the discussion of the LESSEDIT feature below.
1362 %f Replaced by the name of the current input file.
1364 %F Replaced by the last component of the name of the current input
1366 file.
1367 %g Replaced by the shell-escaped name of the current input file.
1369 This is useful when the expanded string will be used in a shell
1370 command, such as in LESSEDIT.
1371 %i Replaced by the index of the current file in the list of input
1373 files.
1374 %lX Replaced by the line number of a line in the input file. The
1376 line to be used is determined by the X, as with the %b option.
1377 %L Replaced by the line number of the last line in the input file.
1379 %m Replaced by the total number of input files.
1381 %pX Replaced by the percent into the current input file, based on
1383 byte offsets. The line used is determined by the X as with the
1384 %b option.
1385 %PX Replaced by the percent into the current input file, based on
1387 line numbers. The line used is determined by the X as with the
1388 %b option.
1389 %s Same as %B.
1391 %t Causes any trailing spaces to be removed. Usually used at the
1393 end of the string, but may appear anywhere.
1394 %T Normally expands to the word "file". However if viewing files
1396 via a tags list using the -t option, it expands to the word
1397 "tag".
1398 %x Replaced by the name of the next input file in the list.
1400 If any item is unknown (for example, the file size if input is a pipe),
1402 a question mark is printed instead.
1403 The format of the prompt string can be changed depending on certain
1405 conditions. A question mark followed by a single character acts like
1406 an "IF": depending on the following character, a condition is evalu‐
1407 ated. If the condition is true, any characters following the question
1408 mark and condition character, up to a period, are included in the
1409 prompt. If the condition is false, such characters are not included.
1410 A colon appearing between the question mark and the period can be used
1411 to establish an "ELSE": any characters between the colon and the period
1412 are included in the string if and only if the IF condition is false.
1413 Condition characters (which follow a question mark) may be:
1414 ?a True if any characters have been included in the prompt so far.
1416 ?bX True if the byte offset of the specified line is known.
1418 ?B True if the size of current input file is known.
1420 ?c True if the text is horizontally shifted (%c is not zero).
1422 ?dX True if the page number of the specified line is known.
1424 ?e True if at end-of-file.
1426 ?f True if there is an input filename (that is, if input is not a
1428 pipe).
1429 ?lX True if the line number of the specified line is known.
1431 ?L True if the line number of the last line in the file is known.
1433 ?m True if there is more than one input file.
1435 ?n True if this is the first prompt in a new input file.
1437 ?pX True if the percent into the current input file, based on byte
1439 offsets, of the specified line is known.
1440 ?PX True if the percent into the current input file, based on line
1442 numbers, of the specified line is known.
1443 ?s Same as "?B".
1445 ?x True if there is a next input file (that is, if the current
1447 input file is not the last one).
1448 Any characters other than the special ones (question mark, colon,
1450 period, percent, and backslash) become literally part of the prompt.
1451 Any of the special characters may be included in the prompt literally
1452 by preceding it with a backslash.
1453 Some examples:
1455 ?f%f:Standard input.
1457 This prompt prints the filename, if known; otherwise the string "Stan‐
1459 dard input".
1460 ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...
1462 This prompt would print the filename, if known. The filename is fol‐
1464 lowed by the line number, if known, otherwise the percent if known,
1465 otherwise the byte offset if known. Otherwise, a dash is printed.
1466 Notice how each question mark has a matching period, and how the %
1467 after the %pt is included literally by escaping it with a backslash.
1468 ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x..%t";
1470 This prints the filename if this is the first prompt in a file, fol‐
1472 lowed by the "file N of N" message if there is more than one input
1473 file. Then, if we are at end-of-file, the string "(END)" is printed
1474 followed by the name of the next file, if there is one. Finally, any
1475 trailing spaces are truncated. This is the default prompt. For refer‐
1476 ence, here are the defaults for the other two prompts (-m and -M
1477 respectively). Each is broken into two lines here for readability
1478 only.
1479 ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x.:
1481 ?pB%pB\%:byte %bB?s/%s...%t
1482 ?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :
1484 byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t
1485 And here is the default message produced by the = command:
1487 ?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .
1489 byte %bB?s/%s. ?e(END) :?pB%pB\%..%t
1490 The prompt expansion features are also used for another purpose: if an
1492 environment variable LESSEDIT is defined, it is used as the command to
1493 be executed when the v command is invoked. The LESSEDIT string is
1494 expanded in the same way as the prompt strings. The default value for
1495 LESSEDIT is:
1496 %E ?lm+%lm. %g
1498 Note that this expands to the editor name, followed by a + and the line
1500 number, followed by the shell-escaped file name. If your editor does
1501 not accept the "+linenumber" syntax, or has other differences in invo‐
1502 cation syntax, the LESSEDIT variable can be changed to modify this
1503 default.
1504
1507 When the environment variable LESSSECURE is set to 1, less runs in a
1508 "secure" mode. This means these features are disabled:
1509 ! the shell command
1511 | the pipe command
1513 :e the examine command.
1515 v the editing command
1517 s -o log files
1519 -k use of lesskey files
1521 -t use of tags files
1523 metacharacters in filenames, such as *
1525 filename completion (TAB, ^L)
1527 Less can also be compiled to be permanently in "secure" mode.
1529
1532 If the environment variable LESS_IS_MORE is set to 1, or if the program
1533 is invoked via a file link named "more", less behaves (mostly) in con‐
1534 formance with the POSIX "more" command specification. In this mode,
1535 less behaves differently in these ways:
1536 The -e option works differently. If the -e option is not set, less
1538 behaves as if the -e option were set. If the -e option is set, less
1539 behaves as if the -E option were set.
1540 The -m option works differently. If the -m option is not set, the
1542 medium prompt is used, and it is prefixed with the string "--More--".
1543 If the -m option is set, the short prompt is used.
1544 The -n option acts like the -z option. The normal behavior of the -n
1546 option is unavailable in this mode.
1547 The parameter to the -p option is taken to be a less command rather
1549 than a search pattern.
1550 The LESS environment variable is ignored, and the MORE environment
1552 variable is used in its place.
1553
1556 Environment variables may be specified either in the system environment
1557 as usual, or in a lesskey (1) file. If environment variables are
1558 defined in more than one place, variables defined in a local lesskey
1559 file take precedence over variables defined in the system environment,
1560 which take precedence over variables defined in the system-wide lesskey
1561 file.
1562 COLUMNS
1564 Sets the number of columns on the screen. Takes precedence over
1565 the number of columns specified by the TERM variable. (But if
1566 you have a windowing system which supports TIOCGWINSZ or
1567 WIOCGETD, the window system's idea of the screen size takes
1568 precedence over the LINES and COLUMNS environment variables.)
1569 EDITOR The name of the editor (used for the v command).
1571 HOME Name of the user's home directory (used to find a lesskey file
1573 on Unix and OS/2 systems).
1574 HOMEDRIVE, HOMEPATH
1576 Concatenation of the HOMEDRIVE and HOMEPATH environment vari‐
1577 ables is the name of the user's home directory if the HOME vari‐
1578 able is not set (only in the Windows version).
1579 INIT Name of the user's init directory (used to find a lesskey file
1581 on OS/2 systems).
1582 LANG Language for determining the character set.
1584 LC_CTYPE
1586 Language for determining the character set.
1587 LESS Options which are passed to less automatically.
1589 LESSANSIENDCHARS
1591 Characters which may end an ANSI color escape sequence (default
1592 "m").
1593 LESSANSIMIDCHARS
1595 Characters which may appear between the ESC character and the
1596 end character in an ANSI color escape sequence (default
1597 "0123456789:;[?!"'#%()*+ ".
1598 LESSBINFMT
1600 Format for displaying non-printable, non-control characters.
1601 LESSCHARDEF
1603 Defines a character set.
1604 LESSCHARSET
1606 Selects a predefined character set.
1607 LESSCLOSE
1609 Command line to invoke the (optional) input-postprocessor.
1610 LESSECHO
1612 Name of the lessecho program (default "lessecho"). The lessecho
1613 program is needed to expand metacharacters, such as * and ?, in
1614 filenames on Unix systems.
1615 LESSEDIT
1617 Editor prototype string (used for the v command). See discus‐
1618 sion under PROMPTS.
1619 LESSGLOBALTAGS
1621 Name of the command used by the -t option to find global tags.
1622 Normally should be set to "global" if your system has the global
1623 (1) command. If not set, global tags are not used.
1624 LESSHISTFILE
1626 Name of the history file used to remember search commands and
1627 shell commands between invocations of less. If set to "-" or
1628 "/dev/null", a history file is not used. The default is
1629 "$HOME/.lesshst" on Unix systems, "$HOME/_lesshst" on DOS and
1630 Windows systems, or "$HOME/lesshst.ini" or "$INIT/lesshst.ini"
1631 on OS/2 systems.
1632 LESSHISTSIZE
1634 The maximum number of commands to save in the history file. The
1635 default is 100.
1636 LESSKEY
1638 Name of the default lesskey(1) file.
1639 LESSKEY_SYSTEM
1641 Name of the default system-wide lesskey(1) file.
1642 LESSMETACHARS
1644 List of characters which are considered "metacharacters" by the
1645 shell.
1646 LESSMETAESCAPE
1648 Prefix which less will add before each metacharacter in a com‐
1649 mand sent to the shell. If LESSMETAESCAPE is an empty string,
1650 commands containing metacharacters will not be passed to the
1651 shell.
1652 LESSOPEN
1654 Command line to invoke the (optional) input-preprocessor.
1655 LESSSECURE
1657 Runs less in "secure" mode. See discussion under SECURITY.
1658 LESSSEPARATOR
1660 String to be appended to a directory name in filename comple‐
1661 tion.
1662 LESSUTFBINFMT
1664 Format for displaying non-printable Unicode code points.
1665 LESS_IS_MORE
1667 Emulate the more (1) command.
1668 LINES Sets the number of lines on the screen. Takes precedence over
1670 the number of lines specified by the TERM variable. (But if you
1671 have a windowing system which supports TIOCGWINSZ or WIOCGETD,
1672 the window system's idea of the screen size takes precedence
1673 over the LINES and COLUMNS environment variables.)
1674 MORE Options which are passed to less automatically when running in
1676 more compatible mode.
1677 PATH User's search path (used to find a lesskey file on MS-DOS and
1679 OS/2 systems).
1680 SHELL The shell used to execute the ! command, as well as to expand
1682 filenames.
1683 TERM The type of terminal on which less is being run.
1685 VISUAL The name of the editor (used for the v command).
1687
1690 lesskey(1)
1691
1694 Copyright (C) 1984-2019 Mark Nudelman
1695 less is part of the GNU project and is free software. You can redis‐
1697 tribute it and/or modify it under the terms of either (1) the GNU Gen‐
1698 eral Public License as published by the Free Software Foundation; or
1699 (2) the Less License. See the file README in the less distribution for
1700 more details regarding redistribution. You should have received a copy
1701 of the GNU General Public License along with the source for less; see
1702 the file COPYING. If not, write to the Free Software Foundation, 59
1703 Temple Place, Suite 330, Boston, MA 02111-1307, USA. You should also
1704 have received a copy of the Less License; see the file LICENSE.
1705 less is distributed in the hope that it will be useful, but WITHOUT ANY
1707 WARRANTY; without even the implied warranty of MERCHANTABILITY or FIT‐
1708 NESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
1709 more details.
1710
1713 Mark Nudelman
1714 Report bugs at https://github.com/gwsw/less/issues.
1715 For more information, see the less homepage at
1716 http://www.greenwoodsoftware.com/less.
1717 Version 551: 11 Jun 2019 LESS(1)